Braces

Does anyone have any advice on dental braces? I am supposed to begin IV chelation soon, but I am also supposed to be getting braces. My orthodontist says that they are made of iron, with a small amount of nickel and titanium, but not to worry since they don't leech. I have high amounts of mercury, lead, arsenic, and cadmium....so do I need to worry about the nickel and titanium?